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Publication numberUS3678155 A
Publication typeGrant
Publication dateJul 18, 1972
Filing dateOct 15, 1969
Priority dateOct 29, 1968
Also published asDE1953943A1, DE1953943C2
Publication numberUS 3678155 A, US 3678155A, US-A-3678155, US3678155 A, US3678155A
InventorsJohn Walter Clippingdale, Charles Andrew Watson
Original AssigneeLever Brothers Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Toothpastes
US 3678155 A
Abstract
Using milled alpha-alumina trihydrate as a toothpaste abrasive can sometimes give rise to corrosion of unlacquered aluminum tubes accompanied by the production of hydrogen gas. This can be prevented by including in the toothpaste a source of monofluorophosphate ions.
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Description  (OCR text may contain errors)

United States Patent Clippingdale et al.

[151 3,678,155 [451 July 18,1972

[541 TOOTHPASTES [72] Inventors: John Walter Clipplngdale, Egham; Charles Andrew Watson, Ruislip, both of England [73] Assignee: Lever Brothers Company, New York,

[22] Filed: Oct. 15, 1969 [2]] Appl. No.: 866,721

[5 6] References Clted FOREIGN PATENTS OR APPLICATIONS 1,559,196 1/1969 France ..424/49 6,803,01 l 9/1968 Netherlands ..424/5 2 Primary Examiner-Richard L. Huff Attorney-Louis F. Kline, Jr., Melvin l-l. Kurtz and Edgar E. Ruff [57] ABSTRACT Using milled alpha-alumina trihydrate as a toothpaste abrasive can sometimes give rise to corrosion of unlacquered aluminum tubes accompanied by the production of hydrogen gas. This can be prevented by including in the toothpaste a source of monofluorophosphate ions.

8 Claims, No Drawings This invention relates to toothpastes and in particular to toothpastes comprising alpha-alumina trihydrate.

in work we have carried out on the fonnulation of toothpastes containing alpha-alumina trihydrate as abrasive cleaning agent, instances occurred in which the alumina gave rise to corrosion of unlacquered aluminum tubes accompanied by the swelling of the tubes due .to the production of hydrogen gas when the toothpaste was stored. These instances of corrosive action occurred when a different method was employed for milling and classifying the relatively coarse hydrated alumina raw material. The alumina trihydrate used in our experiments was made by the Bayer process in which alumina is precipitated from a solution of sodium aluminate, washed and then dried at a low temperature. The corrosive action occurred even at neutral pH and so could not have been caused by any residual alkalinity of the alumina.

We have, however, discovered that milled hydrated alumina having corrosive properties can be stabilized and rendered non-corrosive by including in the toothpaste a source of monoflurophosphate ions. The mechanism of the stabilization of otherwise corrosive grades of alumina is not understood but it may perhaps be due to modification of the surface characteristics of the alumina particles.

According to the present invention, therefore, there is provided a toothpaste contained in an unlacquered aluminum tube and comprising a milled alpha-alumina trihydrate stabilized by including in the toothpaste a source of monofluorophosphate ions, the milled alumina employed being such that without stabilization it would otherwise cause corrosion of the aluminum tube and gassing to occur.

Examples of sources of monofluorophosphate ions that may be employed are the alkali metal, alkaline-earth metal and ammonium monofluorophosphates. Amine monofluorophosphates, such as the triethanolamine salt, can also be used. Other monofluorophosphates, for example stannous monofluorophosphate, can also be employed.

The effective amount of monofluorophosphate may be determined by suitable experiment but will usually be at least 0.1 by weight of the toothpaste. For most practical purposes the amount used will lie between 0.l and 2.5 percent by weight of the toothpaste, the actual amount of the monofluorophosphate depending on the amount of alumina used and the particular monofluorophosphate used.

In order to avoid acid or alkaline attack of the aluminum it is necessary to control the pH so that it is in the range about 6 to about 8. This is conveniently effected by including benzoic acid in the toothpaste.

The invention is applicable to a wide range of toothpaste formulas but is especially applicable to those containing sub stantial amounts of hydrated alumina, such as from 25 to 60 percent by weight of the toothpaste.

The following example illustrates the invention.

EXAMPLE A toothpaste was made to the following composition using a Bayer process alumina which had been milled to a size suitable for use as a toothpaste abrasive cleaning agent.

Peppermint flavor 1.00 Water to l00.00 pH 6.4

When packed in aluminum tubes which were not lacquered internally, and stored for 3 months at 37 C., gassing was found to have occurred within the tube (mainly hydrogen gas) and signs of tube corrosion were noted.

The addition of 8 percent of sodium monofluorophosphate to the above toothpaste product stabilized the alumina Experiments have shown that stabilization is also efi'ected by inclusion of0. 1, l or 2 percent of sodium monofluorophosphate.

Our copending application Ser. No. 707,325 relates to a dentifrice containing a total content of abrasive agent of at least 40 percent by weight, the abrasive agent comprising an amount of at least 30 percent by weight of the dentifrice of alpha-aluminatrihydrate having a particle size distribution such that at least 20 percent by weight of the particles have a size greater than 20 microns. The use of alpha-alumina trihydrate of such relatively large particle size gives dentifrices having very good cleaning properties while causing unexpectedly low damage to tooth enamel. The inclusion of therapeutic materials, for example sodium monofluorophosphate, in these dentifrices is referred to in the copending application. However, the copending application does not refer to the fact that the use of alpha-alumina trihydrate in a toothpaste can sometimes cause corrosion of unlacquered aluminum tubes and swelling of the tubes due to gas production, or to the stabilizing elfect of sodium monofluorophosphate. The use of a monofluorophosphate as a stabilizer in accordance with the present invention is not limited to the use as an abrasive of alpha-alumina trihydrate of any special particle size but the stabilizer can be used if desired with an alpha-alumina trihydrate having a pam'cle size distribution such that less than 20 percent by weight of the particles have a size greater than 20 microns.

What is claimed is:

l. A toothpaste composition contained in an unlacquered aluminum tube comprising from about 25 percent to about 60 percent by weight of milled alpha-alumina trihydrate, and a stabilizer comprising a source of monofluorophosphate ions effective to stabilize said alpha-alumina trihydrate against corrosion of said tubes, said milled alpha-alumina trihydrate normally tending to corrode said tubes.

2. A toothpaste as claimed in claim 1 wherein the milled alpha-alumina trihydrate is stabilized by including in the toothpaste from about 0.1 percent to about 2.5 percent by weight of a monofluorophosphate selected from the group consisting of the alkali metal, alkaline-earth metal, ammonium, amine and stannous monofluorophosphates.

3. A toothpaste composition as claimed in claim 1 wherein the monofluorophosphate is sodium monofluorophosphate.

4. A toothpaste composition in accordance with claim 1 wherein said milled alpha-alumina trihydrate has a particle size such that less than 20 percent by weight of the particles have a size greater than 20 microns.

5. A toothpaste composition in accordance with claim 1 having a pH of about 6 to about 8.

6 A toothpaste composition in accordance with claim 5 which also contains benzoic acid.

7. A toothpaste in accordance with claim 5 wherein said source of monofluorophosphate ions is an alkali metal, alkaline earth metal, ammonium, amine, or stannous monofluorophosphate.

8. A toothpaste in accordance with claim 5 wherein said source of monofluorophosphate ions is sodium monofluorophosphate.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENTNO. 1 3,678,155

DATED July 18, 1972 N I John Walter Clippingdale and Charles Andrew Watson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 10, the number "8" should read -0.8--.

igncd and Scaled this Sixth D a y of August 1985 [SEAL] Arrest.-

DONALD J. QUIGG Attesting Officer Acting Commissioner of Patents and Trademarks

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
FR1559196A * Title not available
NL6803011A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3864471 *Sep 9, 1971Feb 4, 1975Colgate Palmolive CoStable dentifrices containing a monofluorophosphate, an insoluble metaphosphate, and calcium carbonate
US4024239 *Jul 3, 1975May 17, 1977Lever Brothers CompanyToothpaste composition
US4034076 *Mar 3, 1975Jul 5, 1977Lever Brothers CompanyProcess for making toothpaste
US4036950 *Dec 31, 1975Jul 19, 1977Colgate-Palmolive CompanyOral preparations
US4046872 *Oct 2, 1975Sep 6, 1977Colgate Palmolive CompanyDental cream
US4075317 *Oct 2, 1975Feb 21, 1978Colgate-Palmolive CompanyDental cream composition
US4098878 *Oct 23, 1975Jul 4, 1978Colgate-Palmolive CompanyToothpaste containing milled alpha-alumina trihydrate
US4118471 *Jun 9, 1977Oct 3, 1978Colgate-Palmolive CompanyStable dentifrice
US4122164 *Aug 15, 1977Oct 24, 1978Colgate-Palmolive CompanyDental cream composition
US4123517 *Dec 31, 1975Oct 31, 1978Colgate-Palmolive CompanyToothpaste compositions
US4141969 *Feb 22, 1977Feb 27, 1979Colgate-Palmolive CompanyDentifrices containing amorphous silica
US4152417 *Aug 15, 1977May 1, 1979Colgate-Palmolive CompanyDental cream composition
US4160022 *Mar 30, 1978Jul 3, 1979Colgate Palmolive CompanyToothpaste
US4168301 *Jul 19, 1974Sep 18, 1979Lever Brothers CompanyDentifrice based on high particle size alpha-alumina trihydrate
US4170634 *Jan 17, 1977Oct 9, 1979Colgate Palmolive CompanyModified abrasive system for dentifrices
US4248860 *Nov 2, 1979Feb 3, 1981Lever Brothers CompanyDentifrices and their preparation
US4263276 *May 10, 1979Apr 21, 1981Colgate-Palmolive CompanyDentifrices
US4305928 *Dec 9, 1980Dec 15, 1981Colgate-Palmolive Co.Dentrifices
US4309409 *Feb 8, 1980Jan 5, 1982Stauffer Chemical CompanyAnti-corrosion formulation for toothpastes
US4328205 *Feb 2, 1981May 4, 1982Beecham Group LimitedInhibition of corrosion of aluminium tubes by toothpastes
US4394371 *Apr 7, 1982Jul 19, 1983Colgate-Palmolive CompanyDentrifrice preparation
US4421527 *May 23, 1979Dec 20, 1983J. M. Huber CorporationHigh fluoride compatibility dentifrice abrasives and compositions
US4455293 *Nov 17, 1982Jun 19, 1984Colgate-Palmolive CompanyStable dentifrice containing neutral siliceous polishing agent
US4455294 *Nov 17, 1982Jun 19, 1984Colgate-Palmolive CompanyStable dentifrice containing acidic siliceous polishing agent
US4857303 *Sep 14, 1987Aug 15, 1989L'orealDentifrice gel
US4927625 *Aug 18, 1988May 22, 1990Lever Brothers CompanyToothpastes
US4935226 *Aug 18, 1988Jun 19, 1990Lever Brothers Co.Toothpastes
US4935227 *Aug 18, 1988Jun 19, 1990Lever Brothers CompanyToothpastes
US5032383 *Feb 13, 1989Jul 16, 1991Alcan International LimitedAlumina hydrate-containing toothpaste
US5039514 *Dec 12, 1990Aug 13, 1991Alcan International LimitedAlumina hydrate-containing toothpaste
Classifications
U.S. Classification424/52
International ClassificationA61K8/24, A61Q11/00, A61K8/26
Cooperative ClassificationA61K2800/526, A61K8/26, A61K2800/412, A61K8/24, A61Q11/00
European ClassificationA61K8/24, A61K8/26, A61Q11/00
Legal Events
DateCodeEventDescription
May 12, 1988ASAssignment
Owner name: CPPD, INC., C/O CT CORPORATION SYSTEM 208 LASALLE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:LEVER BROTHERS COMPANY, A CORP. OF ME;REEL/FRAME:004888/0628
Effective date: 19880101
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LEVER BROTHERS COMPANY, A CORP. OF ME;REEL/FRAME:004888/0628
Owner name: CPPD, INC., A CORP. OF IL, ILLINOIS
Aug 6, 1985CCCertificate of correction